testXmlParser.cpp

XML parser example.

This example contains the declaration of a class used to read and write data in a xml file like:

<config>
    <range>5.5</range>
    <step>7</step>
    <size_filter>3</size_filter>
    <name>Object</name>
</config>

/*
 * ViSP, open source Visual Servoing Platform software.
 * Copyright (C) 2005 - 2024 by Inria. All rights reserved.
 *
 * This software is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 * See the file LICENSE.txt at the root directory of this source
 * distribution for additional information about the GNU GPL.
 *
 * For using ViSP with software that can not be combined with the GNU
 * GPL, please contact Inria about acquiring a ViSP Professional
 * Edition License.
 *
 * See https://visp.inria.fr for more information.
 *
 * This software was developed at:
 * Inria Rennes - Bretagne Atlantique
 * Campus Universitaire de Beaulieu
 * 35042 Rennes Cedex
 * France
 *
 * If you have questions regarding the use of this file, please contact
 * Inria at visp@inria.fr
 *
 * This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
 * WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 *
 * Description:
 * Example which describes how to use the xml parser class.
 */
 
#include <visp3/core/vpConfig.h>
 
#include <iostream>
#if defined(VISP_HAVE_XML2)
 
#include <visp3/core/vpDebug.h>
#include <visp3/core/vpIoTools.h>
#include <visp3/core/vpXmlParser.h>
#include <visp3/io/vpParseArgv.h>
 
#include <libxml/parser.h>
 
#include <string>
 
#ifndef DOXYGEN_SHOULD_SKIP_THIS
 
#ifdef ENABLE_VISP_NAMESPACE
using namespace VISP_NAMESPACE_NAME;
#endif
 
class vpExampleDataParser : public vpXmlParser
{
protected:
  double m_range;
  int m_step;
  int m_size_filter;
  std::string m_name;
 
  typedef enum { config, range, step, size_filter, name } dataToParse;
 
public:
  vpExampleDataParser();
 
  // Data accessors.
  double getRange() const { return m_range; }
  int getStep() const { return m_step; }
  int getSizeFilter() const { return m_size_filter; }
  std::string getName() const { return m_name; }
 
  void setRange(double _range) { m_range = _range; }
  void setStep(int _step) { m_step = _step; }
  void setSizeFilter(int _size_filter) { m_size_filter = _size_filter; }
  void setName(const std::string &_name) { m_name = _name; }
 
protected:
  virtual void readMainClass(xmlDocPtr doc, xmlNodePtr node);
  virtual void writeMainClass(xmlNodePtr node);
};
 
vpExampleDataParser::vpExampleDataParser() : m_range(0.), m_step(0), m_size_filter(0), m_name("")
{
  nodeMap["config"] = config;
  nodeMap["range"] = range;
  nodeMap["step"] = step;
  nodeMap["size_filter"] = size_filter;
  nodeMap["name"] = name;
}
 
void vpExampleDataParser::readMainClass(xmlDocPtr doc, xmlNodePtr node)
{
  for (xmlNodePtr dataNode = node->xmlChildrenNode; dataNode != nullptr; dataNode = dataNode->next) {
    if (dataNode->type == XML_ELEMENT_NODE) {
      std::map<std::string, int>::iterator iter_data = this->nodeMap.find((char *)dataNode->name);
      if (iter_data != nodeMap.end()) {
        switch (iter_data->second) {
        case range:
          this->m_range = xmlReadDoubleChild(doc, dataNode);
          break;
        case step:
          this->m_step = xmlReadIntChild(doc, dataNode);
          break;
        case size_filter:
          this->m_size_filter = xmlReadIntChild(doc, dataNode);
          break;
        case name: {
          this->m_name = xmlReadStringChild(doc, dataNode);
        } break;
        default:
          vpTRACE("unknown tag in readConfigNode : %d, %s", iter_data->second, (iter_data->first).c_str());
          break;
        }
      }
    }
  }
}
 
void vpExampleDataParser::writeMainClass(xmlNodePtr node)
{
  xmlWriteDoubleChild(node, (const char *)"range", m_range);
  xmlWriteIntChild(node, (const char *)"step", m_step);
  xmlWriteIntChild(node, (const char *)"size_filter", m_size_filter);
  xmlWriteCharChild(node, (const char *)"name", m_name.c_str());
}
 
#endif // doxygen
 
/* -------------------------------------------------------------------------- */
/*                         COMMAND LINE OPTIONS                               */
/* -------------------------------------------------------------------------- */
 
  // List of allowed command line options
#define GETOPTARGS "cdo:h"
 
void usage(const char *name, const char *badparam, const std::string &opath, const std::string &user);
bool getOptions(int argc, const char **argv, std::string &opath, const std::string &user);
 
void usage(const char *name, const char *badparam, const std::string &opath, const std::string &user)
{
  fprintf(stdout, "\n\
Write and read data in a xml file.\n\
          \n\
SYNOPSIS\n\
  %s [-o <output image path>] [-h]\n",
          name);
 
  fprintf(stdout, "\n\
OPTIONS:                                               Default\n\
  -o <output data path>                               %s\n\
     Set data output path.\n\
     From this directory, creates the \"%s\"\n\
     subdirectory depending on the username, where \n\
     dataTestXml.xml file is written.\n\
                  \n\
  -h\n\
     Print the help.\n\n",
          opath.c_str(), user.c_str());
 
  if (badparam) {
    fprintf(stderr, "ERROR: \n");
    fprintf(stderr, "\nBad parameter [%s]\n", badparam);
  }
}
 
bool getOptions(int argc, const char **argv, std::string &opath, const std::string &user)
{
  const char *optarg_;
  int c;
  while ((c = vpParseArgv::parse(argc, argv, GETOPTARGS, &optarg_)) > 1) {
 
    switch (c) {
    case 'o':
      opath = optarg_;
      break;
    case 'h':
      usage(argv[0], nullptr, opath, user);
      return false;
      break;
 
    case 'c':
    case 'd':
      break;
 
    default:
      usage(argv[0], optarg_, opath, user);
      return false;
      break;
    }
  }
 
  if ((c == 1) || (c == -1)) {
    // standalone param or error
    usage(argv[0], nullptr, opath, user);
    std::cerr << "ERROR: " << std::endl;
    std::cerr << "  Bad argument " << optarg_ << std::endl << std::endl;
    return false;
  }
 
  return true;
}
 
/* -------------------------------------------------------------------------- */
/*                               MAIN FUNCTION                                */
/* -------------------------------------------------------------------------- */
 
int main(int argc, const char **argv)
{
  try {
    std::string opt_opath;
    std::string opath;
    std::string filename;
    std::string username;
 
    std::cout << "-------------------------------------------------------" << std::endl;
    std::cout << "  testXmlParser.cpp" << std::endl << std::endl;
    std::cout << "  writing and readind data using a xml parser" << std::endl;
    std::cout << "-------------------------------------------------------" << std::endl;
    std::cout << std::endl;
 
    // Set the default output path
#if !defined(_WIN32) && (defined(__unix__) || defined(__unix) || (defined(__APPLE__) && defined(__MACH__))) // UNIX
    opt_opath = "/tmp";
#elif defined(_WIN32)
    opt_opath = "C:\\temp";
#endif
 
    // Get the user login name
    vpIoTools::getUserName(username);
 
    // Read the command line options
    if (getOptions(argc, argv, opt_opath, username) == false) {
      return EXIT_FAILURE;
    }
 
    // Get the option values
    if (!opt_opath.empty())
      opath = opt_opath;
 
    // Append to the output path string, the login name of the user
    std::string dirname = vpIoTools::createFilePath(opath, username);
 
    // Test if the output path exist. If no try to create it
    if (vpIoTools::checkDirectory(dirname) == false) {
      try {
        // Create the dirname
        vpIoTools::makeDirectory(dirname);
      }
      catch (...) {
        usage(argv[0], nullptr, opath, username);
        std::cerr << std::endl << "ERROR:" << std::endl;
        std::cerr << "  Cannot create " << dirname << std::endl;
        std::cerr << "  Check your -o " << opath << " option " << std::endl;
        return EXIT_FAILURE;
      }
    }
 
    filename = dirname + vpIoTools::path("/") + "dataTestXml.xml";
 
    // Write data using a parser.
    {
      vpExampleDataParser parser1;
 
      // Acquire data from measurments or tests.
      parser1.setRange(3.5);
      parser1.setStep(2);
      parser1.setSizeFilter(5);
      parser1.setName("cube");
 
      std::cout << "Write data to " << filename << std::endl;
      parser1.save(filename);
    }
 
    // Read data using another parser.
    {
      vpExampleDataParser parser2;
 
      parser2.parse(filename);
 
      std::cout << "Read from " << filename << std::endl;
      std::cout << "Range : " << parser2.getRange() << std::endl;
      std::cout << "Step : " << parser2.getStep() << std::endl;
      std::cout << "Filter size : " << parser2.getSizeFilter() << std::endl;
      std::cout << "name : " << parser2.getName() << std::endl;
    }
 
    // Clean up memory allocated by the xml library
    vpXmlParser::cleanup();
    return EXIT_SUCCESS;
  }
  catch (const vpException &e) {
    std::cout << "Catch an exception: " << e << std::endl;
    return EXIT_FAILURE;
  }
}
 
#else
 
int main()
{
  std::cout << "Xml parser requires libxml2." << std::endl;
  return EXIT_SUCCESS;
}
#endif